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Bryan Thompson a907aead99

chore: remove Dockerfile and .gitignore from calculator-rust example

Align with other examples — no example ships a Dockerfile or its own
.gitignore. Rust build artifacts are now covered by the repo-level
.gitignore instead.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

2026-03-13 16:41:30 -05:00

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Calculator Rust Binary Example

Demonstrates packaging a compiled Rust binary as an MCP Bundle using the binary server type. Based on the official Rust MCP SDK calculator example.

What is Binary Server Type?

Unlike node or uv server types where the source code is bundled and executed by a runtime, the binary server type packages a pre-compiled native executable. This is useful for:

Rust, Go, C/C++ MCP servers
Performance-sensitive workloads
Servers with no runtime dependencies

The tradeoff is that binaries are platform-specific — you need a separate build for each target OS/architecture.

Structure

calculator-rust/
├── manifest.json       # server.type = "binary"
├── Cargo.toml          # Rust project
├── .mcpbignore         # Exclude source from bundle
└── src/
    └── main.rs         # Calculator MCP server (~80 LOC)

After building, the server/ directory is created with the compiled binary.

Building

Requires Rust 1.85+.

cd examples/calculator-rust
cargo build --release
mkdir -p server
cp target/release/mcp-calculator server/

Packing

mcpb pack examples/calculator-rust

The .mcpbignore file excludes source code and build artifacts — only manifest.json and server/mcp-calculator end up in the bundle.

Testing

# MCP protocol handshake
echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}' \
  | ./server/mcp-calculator

# Tool call
(printf '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}\n'
printf '{"jsonrpc":"2.0","method":"notifications/initialized"}\n'
printf '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"sum","arguments":{"a":3,"b":4}}}\n'
sleep 1) | ./server/mcp-calculator

Expected: sum(3, 4) returns {"text":"7"}.

Tools

sum — Calculate the sum of two numbers
sub — Calculate the difference of two numbers

Notes

Binary size: ~2.5 MB (stripped, LTO enabled)
The Cargo.toml uses edition = "2024" (Rust 1.85+)
Logs are written to stderr via tracing, so they don't interfere with MCP's stdio transport
Uses the rmcp crate (official Rust MCP SDK)

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